ANALYSIS OF THE PRODUCTION DATA AFTER THERMAL CYCLE SECOND PART CERN, 20th June 2016 Quench Behaviour Team meeting ANALYSIS OF THE PRODUCTION DATA AFTER THERMAL CYCLE SECOND PART E. Todesco CERN, Geneva Switzerland Based on production data (thanks to project engineers and SM18 staff) Based on the HC data of 2015 and 2008 (thanks to MP3 teams)

DATA ANALYSIS: AFTER THERMAL CYCLE About 100 magnet tested, 35 to 60 per series The most interesting case (3000 series) has the fewest  We consider only the first quenches At 6.5 TeV the 3000 series anomaly is very clear Situation is getting more even at 7 TeV, where all firms basically behave in the same way (statistical error at 7 TeV is about 13%) This is not our best estimate for 7 TeV

DATA ANALYSIS: AFTER THERMAL CYCLE Dismantled magnets: Among the magnets tested after thermal cycle, 13 were decollared and coils were replaced In this case the number increased by 500, i.e. 1026 was decollared and became 1526 Out of these 13 magnets, 12 are in the LHC Out of these 13 magnets recollared, 4 have been tested after thermal cycle: 1626, 1643, 2525, 3636 So I remove from the analysis the data relative to dismantled magnets (i.e. 1026, 1143, 2025, …) Ie we consider all problems related to these magnets as understood and solved, and the training data not significative

AFTER THERMAL CYCLE VERSUS HARDWARE COMMISSIONING Comparison between a naive scaling of the After Thermal Cycle (ATC) data and our forecast For the 2000 series we have similar numbers For the 1000 series, ATC would suggest a much larger quenching w.r.t. the 5% I took in a rather arbitrary way (no data available for Gaussian extrapolation) Will we have a 1000 series problem at 7 TeV ? For the 3000 series the HC data are much worse Let us look in more detail in the sample

SAMPLING IN THE 3000 SERIES Very unlucky ! The most interesting batch 3157 to 3208 had only one magnets tested after thermal cycle Removing the initial 100 magnets, we move towards values that are more in agreement with what observed in the HC From 11%±10% on the whole sample, to 20%±18% on the sample excluding the first 100, to be compared to 34% observed in HC At 7 TeV this gives 40%±22%, at the edge of the 67% expected from Gaussian extrapolation So ATC data could be compatible with what observed in HC and what expected based on extrapolation

SAMPLING IN THE 2000 SERIES For 2000 series, large sampling at the beginning, and between 150-200 Data are compatible with the HC to 6.5 TeV, and with extrapolation to 7 TeV (we gave 25% based on Gaussian fit) Quite uniform performance

SAMPLING IN THE 1000 SERIES For 1000 series, large sampling at the beginning, and between 100-150 Worrying data for the 53-104 batch Very scarce sampling afterwards Assuming the first 52 as representative, we will have a ~20% quench probability So probably the estimate (a priori) of 5% was too low

CONCLUSIONS Data after thermal cycle have special features Special sampling, clearly biased, but it can be biased on both sides Large portions of production poorly sampled, in particular the 3000 batch that went in 45 We made the following postprocessing Removed second and third quenches (we had many of them) We remove the magnet that have been disassembled (13 out of 58 tested ATC) We smooth the nonuniform sampling in time After this non trivial massage, we see ATC data can be compatible with HC data to 6.5 TeV (3000 series at the limit) ATC data in line with the Gaussian extrapolation for 2000 and 3000 ATC data suggest to take a 20% probability for the 1000 series in going to 7 TeV

CONCLUSIONS Revised estimate Plus the second quenches - add ¼ to 1/3?